A combination of solid phase extraction, coprecipitation, and neutron activation techniques has been used to develop a speciation
analysis method based on green chemistry for the major arsenic species in drinking water. Arsenate as As(V), monomethylarsonic
acid (MMA), and dimethylarsinic acid (DMA) are separated and preconcentrated by strongly anion and cation exchange columns
in tandem while As(III) remains in the effluent. These species are then selectively eluted and As(III) coprecipitated with
bismuth sulphide. This simple method has been applied to the analysis of water reference materials with good results. The
detection limits are 0.9, 1.7, 1.6, 3.8 and 16 ng mL−1 for As(III), As(V), MMA, DMA and total arsenic, respectively, using a neutron flux of 2.5 × 1011 cm−2 s−1 at the Dalhousie University SLOWPOKE-2 reactor (DUSR) facility and anti-coincidence gamma-ray spectrometry.